Thursday, 3 December 2015

IN-SITU SOIL TREATMENT AND REMEDIATION | CONTAMINATED SOIL REMEDIATION

Soil Remediation for the Environment

Soil contamination or soil pollution is often caused by industrial mining or agricultural activity that leaves chemicals in the ground. Sometimes contaminated soil sites are the locations of

  • chemical leached from waste sites and landfills,
  • where dissolved or suspended chemicals are carried by waste water,
  • leaking underground storage tanks,
  • improper disposal of agricultural or industrial chemicals,
  • lead from bullets contaminating gun ranges.

The biggest pollutants are

  • mineral tailings and waste-flows from mining,
  • lead in soil from various sources,
  • fertilizers and insecticides that are applied incorrectly,
  • oil and fuel dumping.

Prosecution of polluters:

The United States Environmental Protection Agency (EPA) and other agencies monitor and try to regulate levels of contamination in soil in accordance with the so-called "Superfund," or the Comprehensive Environmental Response, Compensation, and Liabilities Act. Under the law the EPA can require those responsible for contamination to clean up polluted soil or pay for the cost of cleanup. Each day of non-compliance after the order can cost the polluter $37,500 for each day of non-compliance.

Environmental Soil Remediation:

Soil Washing--uses surfactants and water. The soil is placed in a wash solution that either dissolve contaminants, or suspend the particles of contaminant in the wash, separated by size, then carrying them away. Bioremediation makes use of microorganisms of fungi to break down organic contaminants (or even petroleum products) so they can be separated from the soil and removed or destroyed.

Thermal Desorbtion--is used for non-organic waste contamination. Contaminated solids are heated to the boiling point of the oil or other contaminants. The liquidized contaminants are pumped away and either to a thermal oxidizer or condensed in a vapor recovery process to be reclaimed (if the contaminant can be re-used).

Thermal soil remediation uses steam and hot air injection, electric current, or other powerful heat-producing methods to bring contaminants to the vapor point along with steam from trapped moisture. The vaporized (or volatilized) contaminants can be stripped away and removed.

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